Wideband differential-to-single-end amplifier

Abstract

The invention discloses a wideband differential-to-single-end amplifier, overcoming deficiencies of a traditional amplifier of a common-gate structure and an LC Balun. The amplifier comprises an input unit, a choke unit, a filter unit, an amplification unit and a Balun unit, wherein positive and negative ends of a differential radio frequency input signal are respectively connected with a positive input end Vin+ and a negative input end Vin- of the input unit, the input end of the input unit is connected with the choke unit, the output end of the input unit is connected with the input end of the filter unit, the output end of the filter unit is connected with the input end of the amplification unit, the output end of the amplification unit is connected with the Balun unit, and the Balun unit outputs a single-end radio frequency output signal. According to the amplifier provided by the invention, power consumption of the amplifier can be reduced, and gain, isolation and phase balance of the amplifier can be improved on the basis of ensuring wideband characteristics.

Description

technical field [0001] The invention relates to an amplifier, in particular to a broadband differential-to-single-end amplifier. Background technique [0002] In various radio transmitters, the RF front-end amplifier is generally a single-ended structure, that is, the RF signal enters from the single-ended input end and is sent out from the single-ended output end. However, amplifiers with a single-ended structure are susceptible to the influence of bonding wires, resulting in gain attenuation problems, so radio transmitters use differential structures to solve the above problems. The output of the transmitter is connected to a single-ended antenna, so the RF front-end of the transmitter needs to have a differential-to-single-ended amplifier, and it is hoped that the amplifier has a certain gain, wider bandwidth, and better phase balance. [0003] Common-gate structure amplifiers are widely used in the design of broadband amplifiers, mainly because they have broadband input...

AI Technical Summary

Problems solved by technology

[0005] The second is the low gain. The gain of the traditional common-gate structure amplifier largely depends on the load impedance, but the large resistance load will bring too much voltage drop, reducing the voltage margin and linearity; and the large inductance load Inductors both increase the chip area and cause the circuit to exhibit narrow-band gain characteristics

[0006] The third is the poor isolation. Due to the poor isolation of the traditional common-gate structure amplifier, this will cause the output signal to return to the input, which is difficult to meet the requirements of the system for the isolation index.

[0007] On the basis of a common-gate structure amplifier, the load resistor is generally replaced with an LC balun to realize the function of differential conversion to single-ended, but the LC balun has frequency-selective filtering characteristics, which will narrow the bandwidth and deteriorate the phase balance. The attenuation of the LC balun is large, so the performance of the differential-to-single-ended amplifier of this structure is poor, and it is not suitable for the RF front-end of the radio transmitter

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